1. Field of the Invention
This invention relates to a unitary seat switch assembly having current overload protection.
2. Prior Art
U.S. Pat. Nos. 3,487,451, 3,704,352 and 3,860,773 to John G. Fontaine and U.S. Pat. No. 4,572,319 to William G. Fontaine show various embodiments of a vehicle seat switch positioned in the driver""s seat of a motor vehicle, such as a car, truck, or golf cart, to be closed by the weight of a person on the driver""s seat and to open automatically when the person leaves the seat. The seat switch may control vehicle brakes, the emergency or parking brake, seat belts, headlights, windshield wipers, or other vehicle components.
Thermistors have been used heretofore for various purposes. The thermistor is a polymeric switch device with a positive temperature coefficient; its resistance increases greatly in response to an overtemperature or overcurrent condition, such as might be caused by a short circuit in some part of the circuit in which the thermistor is connected. In this respect the thermistor can be said to act like a fuse, but it differs from a conventional fuse in that it resets automatically (i.e., resumes its normal low resistance state) when the circuit is de-energized.
The present invention is directed to a novel and advantageous unitary combination of a seat switch and a thermistor that provides overload protection for the electrically operated vehicle component or components controlled by the seat switch and enables a service technician to identify and replace or repair of the faulty device that caused the overload without having to remove the seat switch and thermistor unit from the driver""s seat unless it is determined that the fault is in the seat switch.
Further objects and advantages of this invention will be apparent from the following detailed description of a presently preferred embodiment thereof, with reference to the accompanying drawings.